Cosmetic changes

test/test_utils.py

@@ -2362,6 +2362,8 @@ Line 1
                 <neighbor name="Colombia" direction="E"/>
             </country>
         </data>''')
+        self.assertEqual(traverse_obj(etree, ''), None,
+                         msg='empty str key should return `None`')
         self.assertEqual(traverse_obj(etree, 'country'), list(etree),
                          msg='str key should lead all children with that tag name')
         self.assertEqual(traverse_obj(etree, ...), list(etree),
@@ -2383,9 +2385,9 @@ Line 1
                          msg='`text()` at end of path should give the inner text')
         self.assertEqual(traverse_obj(etree, '//*[@direction]/@direction'), ['E', 'W', 'N', 'W', 'E'],
                          msg='full python xpath features should be supported')
-        self.assertEqual(traverse_obj(etree, (0, '@name', 0)), 'Liechtenstein',
+        self.assertEqual(traverse_obj(etree, (0, '@name')), 'Liechtenstein',
                          msg='special transformations should act on current element')
-        self.assertEqual(traverse_obj(etree, ('country', 0, ..., 'text()', 0, {int_or_none})), [1, 2008, 141100],
+        self.assertEqual(traverse_obj(etree, ('country', 0, ..., 'text()', {int_or_none})), [1, 2008, 141100],
                          msg='special transformations should act on current element')
 
     def test_http_header_dict(self):

yt_dlp/utils/traversal.py

@@ -189,17 +189,22 @@ def traverse_obj(
             elif xpath and not xpath.startswith('./'):
                 xpath = f'./{xpath}'
 
-            findings = obj.iterfind(xpath) if xpath else [obj]
-            if has_specials:
-                result = [
-                    element.attrib if special == '@'
-                    else try_call(element.attrib.get, args=(special[1:],)) if special.startswith('@')
-                    else element.text if special == 'text()'
-                    else None
-                    for element in findings
-                ]
+            def apply_specials(element):
+                if special == '@':
+                    return element.attrib
+                if special.startswith('@'):
+                    return try_call(element.attrib.get, args=(special[1:],))
+                if special == 'text()':
+                    return element.text
+                return None
+
+            if not xpath:
+                result = apply_specials(obj)
             else:
-                result = list(findings)
+                result = obj.iterfind(xpath)
+                if has_specials:
+                    result = map(apply_specials, result)
+                result = list(result)
 
         return branching, result if branching else (result,)